Managing Servers in a Cluster

Cluster management actions are performed from the Servers | Manage Servers page in the Zend Server UI, and allow you to quickly add, remove, enable and disable servers in a cluster.

For more information on working with a Zend Server cluster, watch this video:

See Adding a Server to the Cluster.

This procedure describes how to change a server's name.

Instructions on how to complete a procedure

To edit a server:

  1. In the UI, go to Servers | Manage Servers.
  2. From the Servers list, select the server you would like to edit, and click .
  3. Edit the server name, and click Save.

Disabling a server is used when you would like to remove the server from the cluster, but not lose any of the Monitor and Code Tracing data. For example, before upgrading a server you must disable it. During the disabling process a Graceful Shutdown is performed to ensure your Session Clustering data is not lost.

If you would like to permanently remove a server, in which case all Session Clustering data will be lost, see Removing a Server.

Instructions on how to complete a procedure

To disable a server:

  1. Remove the server you intend to shut down from your load balancing pool. This should be done following the recommended procedure depending on your load balancing configuration.
  2. In the UI, go to Servers | Manage Servers.
  3. Select the server you would like to disable, and click .
    Click OK when a notification asking to confirm your decision is displayed.
  4. The server’s status should indicate that it is disabling. This process may take between a few seconds and a minute, depending on the number and size of sessions and on your network throughput.
The load will increase on active servers during this process since some of the server's sessions are moved to other cluster members.

Enabling a server will make it an active server in the cluster. To be enabled, a server needs to be disabled.

Instructions on how to complete a procedure

To enable a server:

  1. In the UI, go to Servers | Manage Servers.

  2. From the Servers list, select the server you would like to enable and click .

  3. Once the UI indicates that the server has been enabled, return it to your load balancer. This should be done following the recommended procedure depending on your load balancing configuration.

The load will increase on active servers during this process since some of the server's sessions are moved back to the enabled server.

This procedure describes how to remove a server from your cluster. If you are removing the server which hosts the Job Queue service, see Job Queue before performing this procedure.

Instructions on how to complete a procedure

To remove a server from the cluster:

  1. Remove the server you intend to shut down from your load balancing pool. This should be done following the recommended procedure depending on your load balancing configuration.
  2. In the UI, go to Servers | Manage Servers.
  3. Select the server you would like to remove from the cluster, and in the Action bar, click .
    The remove process performs a Graceful Shutdown to ensure your Session Clustering data is not lost.

  4. Click OK when a notification asking to confirm your decision is displayed.

  5. Refresh the Servers list. If the server is no longer listed, it has been successfully removed.
If you plan to remove more than one server, repeat this process for each server after receiving confirmation that the previous server has been removed. Shutting servers down one by one is required to ensure information consistency. While a server is being removed you will not be able to add, edit or remove any other servers.

The server will still be listed in the table but will no longer belong to the cluster. Once a server is removed, you will once again be able to login to the Zend Server UI that is running on the server. All configuration and management actions will now be done directly from the server.

Configurations

Even if there were different configurations on the server before it was added to the cluster, the settings that were given to the server as part of a cluster will stay the same even after it was removed. The one exception to this are the Zend Monitor settings which will be restored to the server after it was removed.

Session Clustering

Removing a server from the cluster initiates a Graceful Shutdown process whereas all the active sessions will be rerouted to the other servers in the cluster. While the graceful shutdown is running, removing additional servers in the cluster is impossible. Once the shutdown is completed, you will be able to remove more servers.

The Force Remove option is made available when a server cannot for some reason be removed from the cluster. This is normally the case when trying to remove the last server from a cluster or when the regular removal hangs for more than a minute. Force Remove releases the user interface on the server's side without performing any shutdown actions that preserve information such as graceful shutdown for session information. The other servers in the cluster will stop communicating with servers that have been removed with Force Remove.

Before using Force Remove, try to access the server you are trying to remove and see if you can locate the reason it could not be removed properly.

Instructions on how to complete a procedure

To force remove a server from the cluster:

  1. Remove the server you intend to shut down from your load balancing pool. This should be done following the recommended procedure depending on your load balancing configuration.
  2. In the UI, go to Servers | Manage Servers.
  3. Select the server you would like to force remove, and click .

  4. Click OK when a notification asking to confirm your decision is displayed.

  5. Refresh the Servers list. If the server is no longer listed, it has been successfully removed.
If you plan to remove more than one server, repeat this process for each server after receiving confirmation that the previous server has been removed. Shutting servers down one by one is required to ensure information consistency. While a server is being removed you will not be able to add, edit or remove any other servers.

This procedure describes how to restart servers in a clustered environment. You have the option to restart all your cluster, or select which servers to restart. The restart is executed according to the Restart Strategy defined on the Administration | Settings page.

Instructions on how to complete a procedure

To restart servers in your cluster:

  1. In the UI, go to Servers | Manage Servers.
  2. From the Servers list, select the servers you would like to restart, or select the whole list to restart the entire cluster.
  3. In the Action bar, click.
    The selected servers will be restarted according to the defined strategy.
This type of restart will perform a full server restart. For more information, see Server Restart.